Gang --	

	This is the fifth  computer  assignment  for  CMPSCI
	145.   You may find this assignment to be difficult,
	or at least a bit tedious, so please get started  on
	it early.

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1.	Download from the class web site the latest  version
	of  a  program called "Build Huffman" and unpack the
	BuildHuffman_Distribution.ZIP file into a folder  on
	your  hard  disk (the archive contains a single .EXE
	file called BuildHuffman.exe).

2.	Launch the program and  then  maximize  the  window.
	Play  with the program for a while to get a feel for
	how it works.  Click on both  round  (internal)  and
	square  (leaf)  nodes,  type  in values, and use the
	arrow buttons in the  tool  panel  to  generate  new
	sections  of  the tree.  When you are done, click on
	the root node and hit DEL enough times to delete the
	entire structure down to the original configuration.

3.	The following text is the first paragraph of Abraham
	Lincoln's  Gettysburg  Address.   The left column of
	the text is column 1 (i.e., there are no  characters
	to  the  left  of  the  text  that you see).  The ??
	characters are used to  denote  the  carriage-return
	(ASCII  code  13)  followed  by the line-feed (ASCII
	code 10) at the right end of each  line.   Carefully
	count  each type of character (how many As, how many
	Bs, etc.) and write that  information  down.   Don't
	forget  to  count  the carriage-returns, line-feeds,
	commas, periods, and spaces.  By my count, the total
	should be exactly 184 characters.

		FOUR SCORE AND SEVEN YEARS??
		AGO OUR FATHERS BROUGHT??
		FORTH ON THIS CONTINENT,??
		A NEW NATION, CONCEIVED IN??
		LIBERTY, AND DEDICATED TO??
		THE PROPOSITION THAT ALL??
		MEN ARE CREATED EQUAL.??

4.	Sort your frequency counts in  descending  order  by
	letter  frequency.   Use  the Huffman code technique
	shown in class to generate a single Huffman tree  of
	the  characters.   You'll  have to do this manually.
	Be very careful!

5.	Use the BuildHuffman program to create an  identical
	copy  of  your  tree.   For each square (leaf) node,
	type in the appropriate character, then hit  F2  (or
	click  the  %  button) and type in the corresponding
	frequency  count.   For  carriage-returns  use   the
	abbreviation  CR,  for  line-feeds  use  LF, and for
	spaces use SP.  Each round (internal) node will show
	the  total  of  all nodes below it in the tree; when
	the tree is complete, the root (top) node will  show
	the  total number of characters in the file.  Verify
	that  this  number  matches  the  total  number   of
	characters you counted in step 4.

6.	Save the text  as  HUFFMAN_lastname_firstinitial.TXT
	(I  would use HUFFMAN_VERTS_W.TXT).  Similarly, save
	the image  as  HUFFMAN_lastname_firstinitial.BMP  (I
	would use HUFFMAN_VERTS_W.BMP).

7.	Compute the total number of  bits  in  the  original
	file  by  multiplying the total number of characters
	by 8 (the number of bits  in  an  ASCII  character).
	Look  at  the  Total Bits entry in the text panel of
	BuildHuffman,  and  then  compute  the   compression
	factor  by  dividing  the  uncompressed total by the
	compressed total.  Using  Notepad,  edit  your  .TXT
	file  created  in step 6 by opening up some space at
	the bottom of the file and typing in the compression
	factor you just computed.  Save the edited file.

8.	Package your .TXT and your .BMP files  into  a  .ZIP
	archive with the string HUFFMAN, an underscore, your
	last  name,  another  underscore,  and  the  initial
	letter of your first name as the name of the archive
	(for example,  I  would  create  an  archive  called
	HUFFMAN_VERTS_W.ZIP).  Email the .ZIP archive to the
	standard mailbox at:
		literacy@cs.umass.edu
	as an email attachment.  In your email message set
	the subject line  to:
		CMPSCI 145 -- HUFFMAN